Effects of Increasing the Allowable Compressive Stress at Release of Prestressed Concrete Girders PDF Download

Author: David Barra Birrcher
Publisher:
ISBN:
Category : Prestressed concrete
Languages : en
Pages : 230

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Author: Christopher Heckmann
Publisher:
ISBN:
Category : Prestressed concrete
Languages : en
Pages : 178

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Author: Brian Schnittker
Publisher:
ISBN:
Category : Prestressed concrete
Languages : en
Pages : 210

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Author: John W. Spencer
Publisher:
ISBN:
Category :
Languages : en
Pages : 96

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Author: Reid Wilson Castrodale
Publisher: Transportation Research Board
ISBN: 0309087872
Category : Concrete bridges
Languages : en
Pages : 603

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At head of title: National Cooperative Highway Research Program.

Author:
Publisher:
ISBN:
Category : Precast concrete
Languages : en
Pages : 666

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Author: Richard A. Miller (Professional engineer)
Publisher: Transportation Research Board
ISBN: 0309087937
Category : Concrete beams
Languages : en
Pages : 202

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Book Description
Introduction and Research Approach -- Findings -- Interpretation, Appraisal, and Application -- Interpretation, Appraisal, and Application -- References -- Appendixes.

Author: Maher K. Tadros
Publisher: Transportation Research Board
ISBN: 030908766X
Category : Technology & Engineering
Languages : en
Pages : 73

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Book Description
"The HCM includes three printed volumes (Volumes 1-3) that can be purchased from the Transportation Research Board in print and electronic formats. Volume 4 is a free online resource that supports the rest of the manual. It includes: Supplemental chapters 25-38, providing additional details of the methodologies described in the Volume 1-3 chapters, example problems, and other resources; A technical reference library providing access to a significant portion of the research supporting HCM methods; Two applications guides demonstrating how the HCM can be applied to planning-level analysis and a variety of traffic operations applications; Interpretations, updates, and errata for the HCM (as they are developed);A discussion forum allowing HCM users to ask questions and collaborate on HCM-related matters; and Notifications of chapter updates, active discussions, and more via an optional e-mail notification feature."--Publisher.

Author: W. Micah Hale
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 282

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Book Description
The use of high performance concrete (HPC) in exterior structures has increased in recent years. Its increased strength and durability make HPC very appealing to the prestressed concrete industry, particularly in bridge girders. Due to its increased strength and durability, HPC can reduce the number of girders, increase bridge spans, decrease bridge depth, and improve bridge durability. Generally, concrete bridges have enjoyed a relatively maintenance free existence. There is some concern that concrete bridge girders should be air entrained; however, the inclusion of air entrainment will reduce concrete strengths. The research program investigated the need for air entrainment in HPC and its effect on HPC bridge girders, and the effects of air entrainment on other important properties.

Author: Jessica Lauren Salazar
Publisher:
ISBN:
Category :
Languages : en
Pages : 352

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Book Description
Pretensioned concrete girders are currently fabricated using 0.5- or 0.6-in. diameter prestressing strands. In recent years, however, it has become of interest to employ larger-diameter 0.7-in. diameter strands to reduce the number of strands and improve the efficiency of pretensioned concrete members. Such a transition requires a considerable initial investment that needs to be justified based on the benefits obtained. Furthermore, the use of 0.7-in. strands would increase the stresses within the end-region of pretensioned elements, which could lead to undesirable cracking and impact the serviceability of the girders. The work presented in this thesis consists of 1) a comprehensive parametric investigation to evaluate the benefits and limitations of using 0.7-in. strands in pretensioned bridge girders, and 2) a full-scale experimental study to investigate the behavior of pretensioned concrete girders with 0.7-in. strands at the time of prestress transfer. The parametric investigation was accomplished by designing thousands of bridge girders with different span lengths, concrete release strengths, and transverse spacings. The results showed that the most noticeable benefit of 0.7-in. strands over 0.6-in. strands was a reduction of up to 35 percent in the number of strands. However, the difference in the total weight of prestressing steel was insignificant. Increasing the release strength of concrete, at least to 7.5 ksi, was found essential to observe benefits in design aspects other than the number of strands. The experimental investigation involved the fabrication of two Tx46 and two Tx70 specimens at the Ferguson Structural Engineering Laboratory. All specimens employed 0.7-in. strands on a 2- by 2-in. grid and the standard detailing currently used for girders with smaller-diameter strands. The observed crack widths in the specimens upon prestress transfer did not exceed those typically observed in Tx-girders with smaller-diameter strands. Therefore, the use of 0.7-in. strands does not seem to trigger a need to modify the end-region detailing in Tx-girders. However, noticeably greater bursting and spalling forces were observed in the end regions of the specimens compared to the demands predicted by AASHTO LRFD provisions. The measured 24-hour transfer length from the specimens also exceeded estimates by AASHTO LRFD and ACI 318-14 provisions.